At the beginning of the 20th century it reportedly had an area of 29,614 square miles (76,700 km2), while the preliminary results of the first Ottoman census of 1885 (published in 1908) gave the population as 645,702. The accuracy of the population figures ranges from "approximate" to "merely conjectural" depending on the region from which they were gathered. It was one of the six Armenian vilayets in the eastern part of Anatolia, and, prior to World War I, had a large number of Armenians living there as well as Georgians, Pontic Greeks and Caucasus Greeks, and other ethnic groups, both Muslim and Christian [mainly Greek Orthodox and Armenian Apostolic (Orthodox/Gregorian)].
In 1893, there were in total 19 Kaza (districts). In all kaza's Muslims (Sunni and Alevi) were the majority. Lowest percentage of Muslims (64%) was in the kaza of Hınıs. Most of the Protestants and Catholics were Armenian.
Population of the Sanjaks, in thousands, according to the Ottoman census of 1893